The Red hair it is the least common of all that human beings can have. It is calculated that they only have it between 1% and 2% of people, although in some places, like Ireland, this figure can be as high as 10%. This makes redheads very special people. So much so that in the Middle Ages redheads came to be considered as witches, different from other women. But they are not only because of the tone of their hair. Also for reasons as curious as its special pain tolerance.
Their sensitivity to it is known to be very different from that of other humans, but the reasons are not entirely clear. For this reason, a team of scientists from Massachusetts General Hospital has conducted research on this, which has just been published in Science Advance.
Of course, the study has not been starred by redheaded people, but red haired mice. The results have been very interesting, but it is clear that the next step will be to see if they can be extrapolated to our species.
Pain, anesthesia and anesthetics
In 2018, Dr. Shalini shah, from UCI Health, explained that variations in pain threshold of redheaded people lead to events such as being more resistant to anesthesia. This makes it necessary to administer higher doses than other patients to obtain the same results.
In fact, a study by the American Dental Association explains that precisely for this reason they tend to be more afraid of dentists. However, when it comes to Take analgesics, they need a lower doseas they are more sensitive to them.
It has also been observed that feel hot and cold more intensely, so they are very sensitive to temperature changes. But what does red hair have to cause all these effects?
What red-haired mice teach us
Redheads show this hue in their hair because of a mutation in the gene that encodes the melanocortin receptor-1 (MC1R).
This is found in pigment-producing cells, called melanocytes. Normally, these melanocytes generate reddish-yellow pigments. However, when they interact with MC1R hormones called melanocurtains, they begin to make darker, black or brownish pigments.
The mutation in people with red hair causes the receptor to not interact correctly with these hormones, so that a increased amount of reddish pigment. The result is that characteristic red hair. But is something else happening?
To verify this, the authors of the study just published analyzed the levels of certain molecules linked to pain in red-haired mice with this mutated gene.
Red-haired people, as well as red-haired mice, have a mutated gene linked to the production of dark pigments
In this way, they found that they secreted lower levels of a molecule called proopiomelanocortin (POMC). To properly exercise its function, it is broken into four hormones, with different functions. The first two are directly linked to the pain. The first sensitizes him and the second blocks him. Lower levels of both would not affect the pain threshold of red-haired people, as their opposite effects would be neutralized. The crux of the matter was in another broken balance.
And it is that another function of these hormones is to regulate the signaling of opioid receptors, which block pain, and those of melanocortin 4, which improve the reception of painful signals.
The drop in these hormones would reduce both effects, but there are other factors outside the melanocytes that can positively regulate opioid receptors, tilting the balance towards them. The result would be that, if it can be extrapolated to humans, redheads and redheads would bear pain better. This means that they need less pain relievers, but are harder to experience the effects of anesthesia.
The truth is that considering red-haired women to be witches is a bit of an exaggeration; but, of course, they are very interesting people. At least from the point of view of genetics.